Therapeutic lamp



Oct. 1, 1929. w. H. CLIFFORD THERAPEUTIC LAMP Filed Sept. 6, 1928/NVENTOR. d/Zm W/%w Patented Oct. 1, 1929 UNITED STATES WILLIAM HUGHCLIFFORD, OF LQNDON, ENGLAND THERAPEUTIC LAMP Application filedSeptember 6, 1928, Serial No. 304,257, and in Great Britain December 19,1927.

The present invention relates to improvements in therapeutic lamps forlight ray treatment and more particularly to the metal casings andfilter holders of such lamps. These filter holders are commonly known inthe trade as screens.

The ventilation of lamp casings generally and particularly theventilation of those sheet metal casings now used in connection withtherapeutic lamps, have engaged the attention of inventors for someyears past and it is a very usual practice to provideventilation holesin front of as well as behind the lamp bulb within a lamp casing.

In an earlier British patent specification in my name No. 233,249 I havedescribed ascreen adapted to hold a light filter comprising two framemembers hinged together to form the filter holder and a loose frameadapted to lie within the holder and to be pressed by springs on theinner wall of one of said hinged frame members against the filter whenin position in the holder. The light openings in the holder thus formedmay be provided with wire gratings to prevent the gelatine or otherfilter from buckling when subjected to the heat of the lamp. The abovedescribed holder is adapted to he slipped into a slide at the mouth ofthe lamp casing.

The present invention provides instead of a separate holder adapted tobe placed in a slide in the mouth of the lamp casing a lamp casing witha cap forming the filter screen adapted to fit over a ventilated flangering at the mouth of said casing, the filter within the cap being heldin the position in use by pressure between the edge of said flange andthe top of the cap.

To carry out the invention the cap may be attached to the mouth of thelamp casing by bayonet slots and locking screws. The filter sheet whichforms the screen may be held in position by a loose inner screen adaptedto lie within the cap against the filter sheets when the latter are inposition. This inner screen is in the form of a sheet metal ring fittedwith cross wires adapted to prevent the filter sheets from bucklinginwards, and is held in position by the edge of the flange at the mouthof the casing when the screen cap is placed in position.

A therapeutic lamp according to the invention is shown by way of examplein the accompanying drawings, in which Figure 1 is a side View of thelamp.

Figure 2 is a section through the lamp cap and the mouth of the lampcasing. showing the filter sheets in exaggerated relation within thelamp cap.

Figure 3 is a perspective view of one of the bayonet fastenings of thecap.

Figure 4; is a plan view of the interior of the cap, and

Figure 5 is a plan view of the loose ring which cooperates with the capto retain the filter in position.

In the drawings a lamp casing a is shown of a. usual form for a highfrequency lamp provided with a series of ventilation holes .7) behindthe lamp adapted to allow the heated air to escape freely from the lampcasing when the lamp is used in a vertical or semivertical position. Asshown in Figures 1 and 2 the mouth of the casing a is provided with aflange ring adapted to receive the ca (Z which forms the screen orholder for the filter sheets. That portion of the flange behind the capis provided with a series of ventilation holes 0 of larger diameter thanthe ventilation holes I) in the body of the casing. These ventilationholes 0 are designed to allow of a rapid and free escape of the heatedair from the casing between the lamp and the filter 72, in the cap (Z.Such a free ventilation is very necessary when filters in the form ofsuperposed gelatine sheets are used for the reason that they runtogether and soon become useless when subjected to high temperatures.Again, if glass filter sheets are employed they may crack from the heatof the lamp unless there is a free escape from the lamp casing for theheated air.

The casing cap (Z which forms the screen or holder for the filter isadapted to be placed on the flange ring at the mouth of the casing a asshown in Figures 1 and 2 and is locked in position thereon convenientlyby nuts 9 on set screws on the flange which screws engage in bayonetslots 6 in the edge of the cap (Z when the latter is placed over theflange.

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The light opening in the cap is conveniently provided with cross wires Zwhich prevent the filter sheets from buckling or bulging through theopening. Similar cross wires m are provided in the light opening of thescreen ring is which is adapted to lie within the cap as shown in Figure2 against the filter sheets when these are in position. This loose innerscreen ring is conveniently in the form of a sheet metal ring as shownin Figure 5. This ring is held in position by contact with the edge ofthe mouth of the casing when the cap is locked thereon.

In Figure 1 I show a lamp casing designed to be mounted on a stand andset at the desired angle by means of the handle 1".

It should be understood that any alternative method of mounting the lampcasing in the horizontal or vertical plane is within the scope of-theinvention. For instance, the lamp casing may be pivoted in a U-framesupported from the ceiling so as to be ad justed as to height and thelamp adapted to hang vertically downwards thereon or horizontally asdesired.

What I claim is i 1 1. A therapeutic lamp casing comprising a ventilatedflange ring at the mouth of the casing, a cap adapted to fit over saidflange ring, filter sheets adapted to liewithin said cap, a loose innerring adapted to lie in said cap between said filter sheets and the edgeof said flange ring when the cap is inposition on said ring and means onsaid ring for preventing the filter sheets from buckling inwards. 2. Atherapeutic lamp casing comprising a ventilated flange ring at the mouthof the casing, a cap adapted to fit over said flange ring, filter sheetsadapted to lie within said cap and a loose metal ring fitted with crosswires to prevent the filter sheets from buckling inwards adapted to liein said cap between said sheets and the edge of said ring when the capis in position on said ring.

3; A therapeutic lamp casing comprising a ventilated flange ring at themouth of the casing, a cap adapted to fit over said flange ring filtersheets adapted to lie within said cap, a loose metal ringfitted withcross wires to prevent the filter sheets from buckling inwards adaptedto lie in said cap between said sheets and the edge of said ring whenthe cap is in position on said ring and aseries of locking screws on theflange ring coacting with corresponding bayonet slots on the edge of thecap forholding said cap on the mouth of the casing.

In testimony whereof I have signed my name to this specification.

' IVILLIAM HUGH CLIFFORD.

